Answer:
1. Yo fui a la manifestación en la Plaza Bolívar. (ir)
2. Mis padres fueron a La Habana de vacaciones. (ir)
3. Tú fuiste un buen amigo en la escuela. (ser)
4. Vosotros fuisteis a la graduación de Paco. (ir)
5. Marisela y yo fuimos novios el año pasado. (ser)
Explanation:
Basics: <em>Ir</em> is to go. <em>Ser</em> is to be.
1. I went to the demonstration at the Bolívar Plaza. In this sentence, subject "I" is going somewhere, making the verb for the sentence ir.
2. My parents went to the Habana for vacation. In this sentence, subject "parents" are going somewhere, making the verb for the sentence ir.
3. You were a good friend at school. In this sentence, subject "You" was a good friend, making the verb ser.
4. You went to the graduation of Paco. In this sentence, subject "you" is going somewhere, making the verb for the sentence ir.
5. Marisela and I were dating/boyfriend and girlfriend last year. In this sentence, subject "Marisela and I" were something, making the verb ser.
